9. keep up　 继续

8. keep silent　 保持沉默

7. keep ... out　　 挡住，留在外面

6. keep out　　 不得入内

5. depend on　　　 依靠，依赖　　　　 keep his words　　 遵守诺言

4. keep on　　 继续不停地做某事

3. keep in touch ... with　　 与...保持联系

2. keep busy doing　　　 不断地，不停地，忙着做某事

1. keep back　　 阻止...向前

13. Every few hundred meters along the wall there are watch-towers, where

　　 soldiers used to keep _____.

Answers: